318 La with 360 heads

If your putting unmodified 340/360 heads on a stock 70's-up 318 you loose static compression on an engine that doesn't have that high of compression to begin with and things get worse if you start to put a larger cam in to take advantage of the larger ports.

Now its not a bad thing if you plan to rebuild the 318 and put pistons in that work for your power goals. At that point, you might look to Magnum heads or an aftermarket head with closed chambers to gain quench. But its all about what your intended goal is.